Synthesis and Monitoring of Nanocars Bearing Different Wheel Types
Chu, Pinlei Edmund
Tour, James M
Doctor of Philosophy
Our group has developed different nanomachines over the years, while some of them are designed to perform in solution phase, a group of molecules termed nanocars were designed to specifically operate on solid surfaces. In this work, wheels, designed to yield better surface and molecule interaction for our studies is synthesized. In the past we have used mainly C60 fullerene wheels for our nanocars molecules. But after we decided to integrate a light activated motor into the nanocars, the fullerene wheels had to be phased out since the fullerene is known to quench the light energy used to actuate the motor. Our group then primarily utilized the p-carborane wheel as it does not show the same quenching effect with the motors. To improve the mobility and diffusion constant of the nanocars, a new generation of wheels was developed, featuring adamantane. A four-wheeled and a three-wheeled fluorescent nanocar was synthesized and monitored, showing enhanced performance to the p-carborane wheeled analogue, which we attribute to the lower surface/wheel interactions. The adamantane wheels were then used to synthesize two nanocars with both a fluorescent 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY) core and a MHz frequency light-activated unidirectional rotary motor, one molecule that is angular and expected to operate in circles and one that is straight and expected to primarily move in a single direction. Preliminary experiments have been conducted and show promising results. While the BODIPY core does quench some of the energy that was supposed to be directed to the motor, the motor still accelerates the nanocar to increase the diffusion constant. The same principle was used to synthesize a molecule with BODIPY core and motor (but without wheels) that could operate in solution. Finally, a two-wheeled nanocar was synthesized with a water soluble extension that could fit into cyclodextrin (CD) cavities and serve as wheels. This nanocar is expected to have very high surface interaction and could be used as to modify surface interactions and the resulting mobility and diffusion constants of nanocars on surfaces.
nanocar; nanomachine, adamantane; cyclodextrin; dipolar; bottom-up